The present invention relates to circuits regulating the operation of high-powered, high-voltage circuits, such as integrated power modules. More particularly, the present invention relates to a safe disconnect circuit for turning off integrated power modules in response to the loss of a control signal.
Integrated power modules (IPMs) and the like function to provide high-current/high-voltage outputs. Given the high-power outputs, switching the modules off/on must be done with considerable care to avoid damaging components or otherwise creating unsafe conditions.
In many cases such modules are constructed to operate in a normally on condition, such that loss of a control signal would not cause the module to turn itself off. This can be useful to avoid unnecessary switching of the module in response to spurious control signals.
However, once it is determined that a pulse in the circuit is causing loss of the control signal, leaving the module in an on condition can create hazards, as the circuit may not be able to be properly regulated.
Accordingly, it is desirable to provide a safe disconnect circuit for interfacing high-voltage/high-current supplies, such as integrated circuit modules.
It is further desirable that the safe disconnect circuit be able to detect and respond to fault conditions, such as open circuits, causing the loss of control signals.
It is further desirable that the safe disconnect circuit be operative to differentiate between spurious variations in a control signal and fault conditions, in order to avoid unnecessary shut down of the IPM in response to such spurious conditions.
It is further desirable that, upon detection of a fault, the safe disconnect circuit generates a signal that turns off the IPM, and holds the IPM in an off condition, notwithstanding the occurrence of spurious input signals.
It is further desirable that the safe disconnect circuit include features to electrically isolate the circuit output signal to the IPM from the circuit input, to avoid potentially hazardous conditions of the input circuit and at the IPM.
These and other objects and advantages are achieved in accordance with the invention as described and illustrated herein.